Effect of Ni substitution for Al on crystal structure and hydrogenation kinetics of SrAl₂ alloy

The effect of partial substitution of Al by Ni on the crystal structure and hydrogenation kinetics of the Zintl phase alloy SrAl₂ was studied by X-ray diffraction (XRD) and hydrogenation measurements. The kinetic parameters and control steps for the hydrogenation of SrAl_2-xNi_x alloys were studied. The results show that the Ni-substituted alloy is mainly composed of SrAl₂, Sr₅Al₉, SrAl and AlNi phases. With the increase of Ni substitution content, the amount of SrAl₂ and Sr₅Al₉ phases decreases, while the amount of SrAl and AlNi phase increases. The maximum hydrogen absorption capacity is decreased, but the hydrogenation kinetics of the alloy is improved greatly after Ni substitution.